its basically imposible to figure out what games are pirated and which are not so that cant be a reason for bans unless you play a game before the official release date then nintendo can know if it has been pirated
They will ask for your serial code and you cant just get some random one because maybe it isnt banned just those things will be harder to lie trust me i called them and tried to figure out why they are banning people
bro this really sucks i called nintendo all they said is that people with the error code are getting banned because they have illigitament applications so nothing we dont know :(